本博客只写一些开发中用到的技术点后续会不断更新就当是个笔记了

爱被打了一巴掌 2022-12-11 07:29 108阅读 0赞

1.mybatis递归查询当前节点下的所有子节点  
sql语句:

SELECT
    	id 
    FROM
    	(
    	SELECT
    		t1.id,
    	IF
    		( FIND_IN_SET( pid, @pids ) > 0, @pids := CONCAT( @pids, ',', id ), 0 ) AS ischild 
    	FROM
    		( SELECT id, pid FROM t_org	t WHERE  t.type ='2' and t.status != '2'  ORDER BY pid, id ) t1,
    		( SELECT @pids := 233883831175143424 ) t2 
    	) t3 
    WHERE
    	ischild != 0

**mapper.xml这么写**

<select id="selectIsChild" parameterType="java.lang.Long" resultType="java.lang.Long">
            SELECT
    	    id
            FROM
            (
            SELECT
                t1.id,
            IF
                ( FIND_IN_SET( pid, @pids ) > 0, @pids := CONCAT( @pids, ',', id ), 0 ) AS ischild
            FROM
                ( SELECT id, pid FROM t_org	t WHERE  t.type ='2' and t.status != '2'  ORDER BY pid, id ) t1,
                ( SELECT @pids := #{id} ) t2
            ) t3
            WHERE
    	    ischild != 0
        </select>

**2.JDK1.8 List<String> 转List<Long>**

请求参数:
    List<String> signupIds;

转化:  
思路就是把List转化成stream流 然后用调用map转化格式在调用collect重新组装成转化格式后的新List

List<Long> ids = form.getSignupIds().stream().map(Long::valueOf).collect(Collectors.toList());

1.**List**<**String>转Long\[\]**

List<String> list = course.getKnowledgeCategoryInfo().stream().map(KV::getId).collect(Collectors.toList());
                                   
    Long[] collect = list.stream().map(Long::valueOf).toArray(Long[] :: new);

**MongoDB分组查询并且取最小时间和最大时间**

db.train_user_node_study_detail.aggregate([
    	{ 
    			$match: { 
    				"userId": "273850549090826221",
    				"trainUserId":"273850548794334856",
    				"trainUserNodeId":"273850555844079950"
    			}
    	},
    	{ 
    		$group:{ 
    			_id:{ "trainUserId":"$trainUserId","trainUserNodeId":"$trainUserNodeId","courseNodeName":"$courseNodeName",},
    			startTime:{ $min:"$startTime"},
    			endTime:{ $max:"$endTime"}
    		}
    	},
    	{ 
    		$sort:{ 
    			startTime:1
    		}
    	}
    ])

查询得到的结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1Rhb1NoYW81MjE_size_16_color_FFFFFF_t_70_pic_center]  
排序正序是1 倒序是-1  
java代码如下:

public MongoStudyDetailResponseResult queryMongoTrainUserNodeStudyDetail(TrainUserNodeStudyDetailForm form) { 
            String uid = UserUtil.getUid();
            Criteria criteria = new Criteria();
            //用户id
            if (StringUtils.isNotEmpty(uid)) { 
                criteria.and("userId").is(uid);
            }
            //train_user_id
            if (StringUtils.isNotEmpty(form.getId())) { 
                criteria.and("trainUserId").is(form.getId());
            }
            //trainUserNodeId
            if (StringUtils.isNotEmpty(form.getTrainUserNodeId())) { 
                criteria.and("trainUserNodeId").is(form.getTrainUserNodeId());
            }
            //聚合查询分组排序操作
            Aggregation aggregation = Aggregation.newAggregation(
                    Aggregation.match(criteria),
                    Aggregation.group("trainUserId", "trainUserNodeId", "courseNodeName").min("startTime").as("startTime").max("endTime").as("endTime"),
                    Aggregation.sort(new Sort(new Sort.Order(Sort.Direction.ASC, "startTime"))));
            AggregationResults<TrainUserNodeStudyDetailEntity> trainUserNodeStudyDetailEntities = mongoTemplate.aggregate(aggregation, "train_user_node_study_detail", TrainUserNodeStudyDetailEntity.class);
            if (CollectionUtil.isEmpty(trainUserNodeStudyDetailEntities.getMappedResults()) || trainUserNodeStudyDetailEntities == null) { 
                return new MongoStudyDetailResponseResult(StudyCode.NO_TRAINING, null);
            }
            //trainUserNodeStudyDetail的所有数据
            List<TrainUserNodeStudyDetailEntity> trainUserNodeStudyDetailEntityList = trainUserNodeStudyDetailEntities.getMappedResults();
            for (TrainUserNodeStudyDetailEntity trainUserNodeStudyDetailEntity : trainUserNodeStudyDetailEntityList) { 
                String courseNodeName = trainUserNodeStudyDetailEntity.getCourseNodeName();
                //取下标为1的是章节
                List<String> collect = Arrays.stream(courseNodeName.split("&&")).collect(Collectors.toList());
                if (CollectionUtil.isEmpty(collect) || collect.size()<2){ 
                    return new MongoStudyDetailResponseResult(CommonCode.SUCCESS, null);
                }
                trainUserNodeStudyDetailEntity.setCourseNodeName(collect.get(1));
            }
            return new MongoStudyDetailResponseResult(CommonCode.SUCCESS, trainUserNodeStudyDetailEntityList);
        }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1Rhb1NoYW81MjE_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/af6601cc5e1643c4bfcbebf0d47750e3.png